Fluid pump



Dec. 24, 1929. B. GREENFIELD FLUID PUMP Filed Feb. 25. 1925 7 4&1

vPint-mea Dee. 24, 1929 UNITED STATES PATENT ori-Ica- BENJ'AMIN GREENFIELD, OF JACKSON HEIGHTS, NEW YORK, ASSIGNOB T0 OOMBUS- TION UTILITIES CORPORATION, OF NEW YORK, N. Y., A CORPORATIONAOF MAINE FLUID PUMP Application led February 25, 1926. Serial No. 90,439.

The present invention relates to multiple fluid feed systems and more particularly to a compact arrangement of oil pump and air blower units suitable for supplying oil and `tir separately to a domestic heating systen1.

The oil feed requirements of the burners 1n domestic oil fired heating systems are quite commonly taken care of by small pumplng units which are located at some point between the burner and the source of oil suply. In many instances the source of fuel supply for such systems is a reservoir or storage tank located underground and quite often below the level of the burner. The feed pump 1s, therefore, employed both to raise the oil from this underground storage and to deliver it preferably at a relatively low and uniform pressure and at a controlled rate to the burner. To insure efficient combustion ofthe oil, air or steam under pressure is commonly employed to effect thorough atomization of the oil as it enters the combustion chamber of the furnace. Vhen air is used as the atomizing agent a small fan or blower is employed to deliver the air to the burner at a controlled rate and under a suitable pressure for effective atomization of the oil.

For the greater convenience and comfort of the householder most domestic oil burning heating systems are now being designed for automatic regulation of the fuel and/or air supply in accordance with the heat requirements of the house. Thus the heat requirements of the house may be measured by a thermostat positioned at a suitable point and the measurements thus taken are then used to control the operation of the pump supplying the feed to the burner and/or of the blower or dampers governing the supply of atomizing medium or air for combustion. The heat requirements of the house are preferably measured byone instrument, and ac.

cordingly ,it is desirable to concentrate the control of both the fuel and air supplies to the burner by said instrument at one point. In order to permit the use of a simple thermostatic control of domestic heating systems and also of domestic refrigerating systems and similar systems using two or more kinds of fluid it Would appear to-be distinctly advantageous to assemble the pumping units supplying the feed requirement of such systems into a dual or multiple pumping unit which can be governed by simple thermostatic control applied for instance to an electric motor drive common to all parts of said unit.

The primary object of the present invention is to provide a compact assembly of multiple fluid pumping units embodying the advantageous features outlined above.

` While it is sometimes permissible to mix the two kinds of fluid commonly required by domestic heating and refrigerating systems in the workinvr chambers of the umps supplying the fee at other times, as or instance,

V1n taking care of the supply of oil and air to the oil burners of certain standard types of domestic heating furnaces, it is highly desirable to carry on the atomization and va-. porization of the oil substantially simultaneously, and accordingly it is very undesirable to allow any intermingling of the air and oil prior to the instant that they leave the atomizing'tip of the burner.

According y another object of the present invention is to provide a compact assembly of fluid pumps arranged to receive power from a common prime mover through a common shaft and to deliver different kinds of fluid directly from the sources of supply to the place of use without any intermingling in the course of transit.

A specific feature of the invention contemplates a compact assembly of oil pump and air blower units arranged' to receive power from a common prime mover through a common shaft and to deliver restricted quantities of air and oil'at uniformly low and controlled pressures directly from the sources of supply through separate lines to the burner of a heating system.

Another feature of the invention contemplates assembling the separate pumps supplying the fluid feed requirements of a multiple fluid feed system and the prime mover for actuating said pumps into a' compact form so that they can all be encased in a single odor and sound proof housing.

With these andvother objects and features in View the invention consists in the multiple fluid pump assembly hereinafter described and particularly defined in the claims.

The various features of the invention are illustrated in the accompanying drawings. in which Fig. 1 is a view in vertical section wlth parts in elevation of a dual fluid pump and motor drive assembled in accordance with the compact arrangement embodying the preferred form of the present invention; Fig. 2 is a cross-sectional view through the end plate of the smaller pump, taken on the line 2-2 of Fig. 1 looking in the direction of the arrows;

Fig. 3 is a cross-sectional view through one section of the larger pumping unit, taken on the line 3 3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a cross-sectional view taken through another part of the larger unit on the line 4-4 of Fig. 1, looking in the direction of the arrows;

Fig. 5 is a cross-sectional view through the common end plate between the two pumplng units, taken on the line 5-5 of Fig. 1 looking in the direct-ion of the arrows;

Fig. 6 is a cross-sectional view through the smaller pumping unit, taken on the line 6-6 of Fig. 1 looking in the direction of the arrows, and

Fig. 7 is a view in vertical section of an alternative form of end plate for use between the two pumping units illustrated in Fig. 1.

In the drawings the numeral 10 indicates an electric motor, preferably of some standard type, having its casing joined by a flanged connection 12 with the casing of a lubricating oil storage chamber 14. The casting 16 which houses chamber 14 is illustrated as forming one end plate of a large pumping unit 18 composed of two cylinders, Figs. 1, 3 and 4. Pumping unit 18 is shown as constructed of two castings 20 and 22 held apart by and preferably tightly bolted to a common partition casting 24.

For ease in description it will be considered that the combined pump assembly illustrated in the drawing is to be used for supplying air and oil to the vaporizing nozzle .of an oil burning furnace, and that the two castings 20 and 22 house the working parts of a two cylindered air blower 18 which is separated from an oil pump 26 housed in a casting 28 by a common side plate casting 30, Fig. 1. A casting 32 forms the other side plate of oil pump casting 26 and also houses a bearing in which the free end of a drive shaft 34, common to all of the working parts of both pumps, is journalled. The adjoining surfaces of flange 12 and of the castings 16, 20, 22, 28, 30 and 32 are all preferably machined and tightly bolted together to form leakage-proof joints, in order that the motor 10, air blower 18 and oil pump 26 will form a unitary structure such as that illustrated,

the details of which are to be more fully hereinafter described.

While the larger pumping unit 18 will be hereinafter described as an air blower and the smaller pumping unit 26 as an oil pump, this is simply for ease in description and is not intended to in any way limit the scope of the invention, since it is obvious that pumps 1-8 and 26 may be used e ually well for han- ;llling many other types o liquid and gaseous uids.

The air blower 18 has been shown as an assembly of three separate castings but this is not material because it has been .found feasible to make up the two sections of the air blower and the partition 24 into one unit casting. The assembly of the air blower illustrated in the drawings includes a working cylinder 36 housed in casting 20 (see Fig. 3) and another working cylinder 38 housed in casting 22 (see Fig. 4). Castings 16 and 24 form respectively the side walls of cylinder 36 and similarly castings 24 and 30 form respectively the side walls of cylinder 38. Shaft 34 extends centrally through cylinders 36 and 38 and is directly connected in alignment with the shaft 40 of motor 10 by a flexible coupling 42.

Although the principle underlying the design of blower 18 and pump 26 forms no part of the present invention, the design and operation of the blower and pump will be described as an aid to understanding the invention.v

Air or other fluid to be handled by blower 18 is sucked in through a screen 44 (see Fig. 2) and first enters that section of the blower housed in casting 20 through a port 46 (see Fig. 3).

Referring to Fig. 3, a pivoted link or hinge 48 is shown forming a suction chamber 50 on its upper side into which the air enters through port 46. From chamber 50 the air is drawn into cylinder 36 through a passage 52 lying to the right of link 48 in the drawings. A hollow cylindrical piston 54 is mounted eccentrically in cylinder 36 on a bearing 56. A cam 58 is journalled in the bearing 56, and said cam is formed eccentrically on shaft 34. Cylindrical knobs 60 are fitted on each end of link 48 and these knobs are journalled in cylindrical grooves 62 in casting 20 and in the outer periphery of piston 54, respectively. By this arrangement link 48 serves not only as a partition between the suction and discharge sides of blower cylinder 36 but also as a movable hinge which links piston 54 with casting 20 and prevents the piston from revolving but permits the piston to be pushed around by the rotation of shaft 34 and eccentric 58 in contact with the inner surface of cylinder 36 to wipe the surface of the cylinder and thus force air ahead of it. As it revolves, piston 54 pushes air out through a passage 64, shown to the left or underside of link 48 in the drawings, into a discharge chamber 66. Blower 18 may build up considelgble pressure behind an orifice in the oil burner or other place 'of use (not shown). The air thusdelivered under pressure into chamber 66 passes through a ort 68 into a discharge chamber 70 in the of casting 22 (see Fig. 4) A part and at times all of the air admitted to the blower unit through screen 44 and port 46 passes through a port 72 into a suction chamber 74 in the lower portion of casting 22. A hollow annular piston 7 6 ismounted eccentrically in cylinder 38 of casting 22 on bearing 78, in which a cam is journaled. Cam 80 is turned eccentrically on shaft 34. Cams 58 and 80, with the two pistons which they support in cylinders 36 and 38 respectively, are preferably set at an angle of 180 apart on the drive shaft. With this arrangement blower 18 serves as a double acting pump to deliver a substantially continuous and uniform flow of air to the burner or other place ofuse. Morever, with this arrangement the two pistons 54 and 76 balance each other'mechanically, thus permitting the drive shaft 34 to rotate at a high speed with a minimum amount of vibration. Y

In the drawings air piston 76 Fig. 4 is shown in a position which it assumes at the instant when no air is either entering `0r leaving cylinder 38, while piston 54, Fig. 3,

is shown in the position which it assumesy when the suction ports and exhaust ports of cvlinder 36 are both wide open. As piston 76 moves upward from the position shown in Fig. 4, air is drawn in througha port 82 lying to the right of a partition link 84 and at the same time a port 86 to the left of link 84 is gradually thrown open to permit air to exit into discharge chamber 70 from a clearance space 88 formed between theinner wall of cylinder 38. and the outer wall of piston 76. Knobs 90 on the ends of link 84 are fitted into cylindrical grooves 92 in casting 22 and in the periphery of piston 76 respectively, thus forming with link 84 a hinge pivoting piston 76 to casting 22 and preventing piston 76 from rotating with .shaft 34 and cam 80. Thus air under pump pressure is fed continuously into chamber 70 from at least one of the two blower sections and a continuous stream of air under substantially uniform pressure is conducted off through a port 94 and oil separator 96 to the burner orvother place of use. The unction of oil separator 96, which may be o any suitable type, is to remove lubricating oil used in the blower unit from the stream of pressure air or other fluid' delivered bythe blower and to return oil thus separated to oil storage reservoir 14 through a drain 97. A pressure relief Vvalve 98 is shown mounted on the delivery line of the blower, its function being to regulatethe E back-pressure built up on the blower andthe ase quantity'lof air passed through a discharge opening 99 tothe burner or other place o f use.

The details of design and operation of the smaller pumping unit 26 (oil pump) will now be\briefly considered. Oil or other fluid to be delivered by the pump is drawn from a storage tank or other source of supply, preferably located below the pump, through a pipe 100 into a passage 102 ported out of pump casting 28 (see Fig. 6). The principal underlying pump 26 is the same as that underlying each section of the air blower' 18 already described. A working cylinder 104 is housed within casting 28 and a piston 108 is mounted jeccentrically of cylinder 104 on an eccentric cam 106 formed on drive shaft 34. A link 110, similar in its design and functions to links 48 and 84 in blower unit 18, divides the lower portion of oil pump 26 into a suction chamber 112 and a discharge Alength of cylinder 104 as measured by the disy tance between the inner walls of end plate casting 30 and 32 respectively, and the opposite edges of link 110 are preferably mafaces of castin s 30 and 32 in order to Jrevent substantial le. vage between'suction cliamber 112 and discharge chamber 114 as piston 108 oscillates back and' forth in'cylinder 104. Oil entering the smaller pump through port 102 is drawn through a passage 120 into suction chamber 112 and from there it enters a clearance space 122, formed between the outer periphery of piston 108 and the inner walls of cylinder 104, through a port 124. As the drive shaft rotates oil thus admitted to cylinder 104 is pushed around by the action of piston 108 until it enters discharge chamber 114 .on the under side oflink 110 through a port 126. VFrom discharge chamber 114 the oil, now under pressure built un by the pump, is conducted to a flow restricting device 128, shown inFig. 1 as housed incasting 32.

1W'hile this flow restricting device 32 forms no part of the present invention it will now be brieiiy described as an aid to a better vunderstanding of the present invention. .The `amount of oil normaly required by the burner in an oil {ired house heating installation makes a very small stream. Accordingly the flow restricting device illustrated in the drawing has been developed with the idea of applying it to a pump unit of 'suiiicient capacity to give satisfactory and efficient servllO 100 chined to hug closely the machined inner surice. At the same tinfie this levice avoids fre uent sto a es rom c ogglng up w1 dus(l. or rust slegcarried by the working fiuid which are common occurrences in an oil or other fluid feed system in which small pin point orifices are used in the delivery hne of a pump of convenient capaclty 1n order to cut down the flow of fluid passed from the pump to the burner or other place of use. The device illustrated in the drawmgs comprises essentially a small pressure chamber 130, normally closed by a cap screw 132, which is connected with an annular passage, 134 leading ofi' from pump discharge chamber 114 by a short passage 136 (see Fig. 1). The lower portion of pressure chamber 130 is narrowed down and ported out through a small passage 138 into the bearing in which the free end of drive shaft 34 is journaled (see Fig. 2). An axial recess 140 is drilled in the end of shaft 34 and a radial aperture 142 is cut into the walls of recess 140 in a position where it will register at every revolution of the shaft with the ported opening from passage 138. A delivery line 144, leading from the pump preferablv to the burner or other place of use, cbnnects with the small reservoir formed in the recessed end 140 of shaft 34 by means of a fitting 146.

It has been found impracticable to bulld a pump ot' the type illustrated in the drawing of such small capacity as to handle only the amount of oil normally required to supply a single domestic oil burner. Accordingly pump 26 is made of a convenient size and an overflow arrangement is provided whereby excess oil handled by the pump which is not required at the place of use can be returned to the oil storage tank or other source of supply. The principal elements of this overfiow arrangements are shown in the drawings as housed in the casting 30 already mentioned as comprising a common end plate between cylinder 38 ofblower 18 and the single cylinder 104 ot' pump 26. The arrangement includes a short passage 148 which opens out into a reservoir 150 at the unction of annular passage 134 with passage 136 on the pump side of the flow restricting device. Reservoir 150 is normally sealed from the atmosphere by a plug 152 in the outer periphery of pump casting 28 (see Fig. 6). At its opposite end passage 148, shown in dotted lines in Fig. 1, is connected by an opening 154 (see Fig. 5) with the end ofa piston chamber 156 built into casting 30. Chamber 156 contains a pilessure relief valve to maintain a predetermined pressure on the oil being pumped. In the drawings chamber 156 is shown with its major axis in a horizontal plane at right angles to the axis of drive shaft 34, although its position is not material. A plunger 158 is mounted in chamber 156 and a compression spring 160' positioned behind the plunger 158 is arranged to force the plunger to the right as viewed in Fig. 5 but not to the extent of closing port 154. Spring 160 has one end resting against the plun er 158 while its other end is fixed to a hea 162 on a set screw 164. Set screw 164 is in turn adjustably mounted in the threaded bore of a nut 166, form-ing a closure for the end of chamber 156. Thus screw 164 projects through nut 166 and is normally covered by aprotecting cap 168. The parts of the mechanism are illustrated in Fig. 5 in a position which they assume when the oil pump is not running. As soon as the oil pump starts up the pressure built up by the pump against the fiow restrictingr device 128 in chambers 130 and 114 forces plunger 158 to the left so as to uncover more or less of a port 170, shown in dotted lines in Fig. 5. As soon-as port 170 is opened by the backward movement of plunger 158 oil may pass from the pressure side of plunger 158 through a by-pass 172 in the wall of cylinder 156, and out into chamber 156 through a port 174. In passing from the right to the left side of plunger 158 the pressure on the oil is removed and it is then free to enter an anular chamber or reservoir 176. formed in casting 30 around a bearing 178, through a passage 180, Figs. 1 and 5. Chamber 176 is provided with a pipe opening 182 through which the overflow fom the pump may be returned to the storage or suply tanks (not shown).

Small pump 26 will ordinarily be employed for supplying the fluid for which there is the least demand4 at the place of use. Thus whenever the dual pumping unit illustrated in the drawing is used to take care of the fuel and air requirements of an oil burner, pump 26 will be preferably employed to take care of the oil supply and as a rule it will derive sufficient lubrication from the oil itself. For this reason no special means have been illustrated whereby to effect the lubrication of the bearing surfaces of pump 26. v

To lubricate the blower unit a small copper 4tube 184 (see Fig. 1) has one end immersed in the lubricating oil normally stored in the lower portion of casting 16 and its other end is sweated into a hole 186 drilled in that portion of casting 16 which forms the end pla-te of cylinder 36 in blower 18. A similar hole 188 (see Fig. 3) of a size to match hole 186 is drilled through the adjoining side plate of piston 54 (shown in dotted lines in Fig. 1) so that for an instant during each revolution of the drive shafts the holes 188 and 186 in the piston and in the end plate respectively, register to allow a small amount of lubricating oil to be drawn by blower suction into the hollow central portion of piston 54. From this point the oil drains out itno the suction side of the blower through a small passage 190 drilled in the cylinder wall. From here some of the oil is carried by the inflowing air through port 72 into the suction chamber 74 in the base of casting 22, so that the oil finds its way thoroughly through both sections of the blower with the incoming air and is eventually caught in the air separator 96 and returned to reservoir 14 for use over and over again. Very little oil is normally required for eliicient lubrication of the small capacity blowersemployed in supplying air to domestic heating units. Accordingly the 'chief function of the lubricating system is to feed voil reliably-in small quantities through the blower in amounts that will not overburden the separator on the air discharge lines, thus permitting dry air to go to the burner and preferably one filling of oil in storage tank 14 to last through a heating season. Due to the rapidity with which shaft 34 and flexible coupling 42 rotate it is desirable to maintain the level of the oil in chamber 14 well below the lower periphery of the coupling. A removable cap 192 permits access to chamber 14 and this cap is preferably arranged to prevent loss from the chamber 14 of any oil thrown up by the rapid rotation of coupling 42. Chamber 14 is vented to the atmosphere by means of a fitting 193 in cap 192.

As already pointed out, one of the chief objects of the present invention is to provide a compact assembly of dual fluid pumping units which will function to deliver tWo kinds of fluid separately from sources of supply to a place of use without any intermingling of the fluids in the chambers of the pumps or elsewhere in transit. In order to effect this object the particular pump assembly embodying the preferred form of the present invention, includes means for substantially pre- AAventing the intermingling of air handled by blower 18 with oil handled by pump 26 through the leakage which might normally occur along the clearance space formed between the outer surface of that portion of shaft 34 journaled in casting 30 and the inner surface of bearing 178. As shown in Fig. 1 the central portion of bearing 178 is ported out at a number of points 194 into the annular chamber 17 6' at the head of the overiow line from pump 26. Furthermore, that end of bearing 178 lying adjacent cylinder 38 of blower 18 is chamfered to form a small annular passage 196 entirely surrounding shaft 34, and the adjacent end of piston bearing 56 in which cam 58 is journaled is similarly chamfered to form an annular passage 198 surrounding that portion of cam 58 lying immediately adjacent the end wall of cylinder 38. As the drive shaft rotates passages 196 and 198 are always in communication at some point (see Fig. 1). Atmospheric pressure is maintained in the two annular passages 196 and 198,1 ing at the junction point of hearing 178 and lower cylinder 38, by means of a radial aperture 200 ported out at one end into passage 196 and at the other end into a passage 202 in the bore of shaft 34, passage 202 in turn opening out into oil storage chamber 14 through the open central portion of .coupling 42. Through this arrangement 1t is possible to maintain atmospheric pressure on the air blower end of bearing 178 and at the same time to employ enough suction on the return line leading from chamber 176 so that a little oil will be carried through the bearing from pump 26 to passages 194, and possibly also a small amount of air may be drawn up into chamber 176 from blower 18 and annular passage 196. The oil drawn through bearing 178 from pump 26 will serve to lubricate that portion of the bearing lying to the right of passages 194 and will not be lost, since it is returned from chamber 176 to storage and thence back to the suction side of the pump. By maintaining atmospheric pressures in passages 196 and 198 the rapid rotation of shaft 34 will cause a large number of air bubbles to collect around that portion of the periphery of the shaft immediately adjacent passage 196, and these air bubbles will act to dam ofi' any oil which might otherwise leak past passages 194, so that no oil can enter cylinder 38 of blower 18 along bearing 178. The principle underlying this idea of damming olf the oil by means of air bubbles is substantally the same as the principle underlying the interference in the operation of a hyperdermic needle or a fountain pen sometimes caused by air trapped in the capillary entrance of the reservoir. As the passages 196 and 198 are opento the at-mospherethrough bore 202 none of the back-pressure built up by the blower 18 is felt along bearing 178, so that the collection of air bubbles encircling the shaft 34 adjacent pasage 196' and any oil held back of the dam thus formed serves to effectively block 0E air which might other- Wise be drawn along the bearing to the ports 194, with the result that there is slight danger 0f air leaking along the bearing past passages 194, even in cases where a pressure below atmosphere exists in the working cylinder of pump 26.

When the unit is idle the combined effect of the oil return pipe connecting chamber 17 6 to the storage or other source of supply and of the pump suction pipe 100 will maintain an oilA pressure at ports 194 slightly less than atmospheric. This may cause air to be drawn in along the shaft from the blower and out through ports 194 into chamber 17 6. Any air thus leaking through into chamber 17 6 will pass out through port 182. As air accumulates at this point oil trapped in the line from 182 back to storage will gradually be displaced until the oil pressure in chamber 176 becomes less than in the pump itself. Oil will then begin to flow from chamber 17 6 back through the pump bearing 178 into pump cylinder 104 and thence back to underground storage through the pump suction line. Until oil trapped in chamber 176 has all been depleted, however, no air can enter the pump itself nor the feed system of which it is a art. This arrangement, therefore, has a dlstinct advantage 1n any oil burner feed system since, with a direct pump feed from storage to the oil burner, any small air bubble passing to the burner with the fuel operates momentarily to extinguish the flame, which is obviously to be avoided.

The combined pump and blower unit illustrated in Fig. 1 of the drawings has been designed primarily for use in a fluid feed system wherein the source of supply of oil or other fluid handled by the small pump 28 is located in a plane below the level of the pump. In other words, the assembly illustrated in Fig. 1 was designed primarily for supplying oil or other Huid continuously and directly lfrom underground storage located below the level of the pump to the place of use. However, it has been found that in many cases it is necessary to locate a combined iuid pumping unit of this type in a plane below the plane of the storage tank or other source of supply of the fluid handled by the small pump. The assembly illustrated in Fig. 1 can be readily adapted to asystem of this type, i. e., one having an overhead supply for the small pumping unit. However, it has been thought advisable to illustrate in Fig. 7 of the drawing an alternative arrangement of the end plate casting 30 de' veloped particularly for use in a combined blower and pump unit of the class described in cases where the storage tank or other source of supply of fluid handled by the small pump unit is' located in a plane above the level of the pump. The alternative or modified form of end plate 30 illustrated in Fig. 7 of the drawings differs essentially from the preferred arrangement shown in Fig. 1 in the following respects A narrow cylindrical casting or disk 204 is inserted between end plate casting 30 and pump casting 28. Likewise bearing 178, illustrated as in one piece in Fig. 1, is divided into two part's or sections 206 and 208 in the modified end plate assembly illustrated in Fig. 7. That section of the drive shaft bearing illustrated as 206 in Fig. 7 is mounted on shaft 34 to form a drive it between the periphery of the shaft and the wall of an axial core drilled through casting 204. That portion of casting 30 adjacent the left hand face of casting 204 in the drawing is drilled to slightly larger bore than that of the casting 204 so tha the bearing 206 forms an easy fit with t e bore of that portion of casting 30. That portion of casting 30 lying adjacent blower casting 22 is drilled to a somewhat larger bore and bearing 208 is mounted with a drive tit between this portion of casting 30 and the periphery of drive shaft 34. Casting 30 of the modified end plate arrangement illustrated in Fig. 7 is deslgned to house the barrel 156 and other working parts, including by-pass 172, of the relief valve assembly illustrated in Figs. 1 and 5. Likewise castin 30 is arranged to house the chamber 176 and and overflow system similar in general to that shown in Fi s. 1 and 5 in the drawing, but with this di erence, namely, that chamber 176 and ports 194 forming the oil seal gland in this case are in communication only with the oil pump side of the end plate assembly and are positively isolated from the air blower of the assembly by a pocket seal gland 210 housed in bearing 208. This pocket gland is filled with packing which is compressed by the action of a compression memer 212 connected with and held apart from bearing 206 by a compression spring member 214. With this arrangement no positive obstruction is presented to the leakage of oil from overhead storage throughthe overflow port 182 into chamber 176 and thence along the shaft through bearing 206 into the oil pump. However the pocket gland 210 in the blower side of casting 30 acts to prevent any leakage of oil from chamber 176 along shaft 34 into the adjacent blower unit. The modified end plate assembly illustrated in Fig. 7 is so designed as to be readily removable for the repacking of pocket gland 210 simply by loosening the set screws holding end plate casting 32 and casting 28 of the oil pump and moving each of these castings and casting 204 with its tightly fitted bearing 206 to the right sufliciently to uncover pocket 210.

the dual fluid feed system which forms the subject of the present invention is particularly adapted for taking care of the fluid feed requirements of domestic heating or refrigerating systems, for instance domestic oil burners, not only because it is sturdy in construction and reliable in operation, but' also because it is assembled in a compact unit which can be housed in an odor and soundproof box and its operation is attended with a minimum amount of vibration. By mounting both pumping units on a common shaft actuated by a common prime mover it is pos'- sible to control the dual fluid feed simply from one point, if desired. B means of the oil sealing gland above descri ed it is possi.- ble not only to operate both pumps from a common prime mover through a common shaft, but also to materially cut down the weight of the assembled unit by the use of a common endplate separating the working cylinder of one pump from the working cylinder of the other. If a sealing gland were not introduced between the two pumps, when the combined unit was used for sup lying air and oil to a domestic oil burner, ihr instance, there would be a considerable amount of mingling of air and oil in the working ports 194 of an oil seal gland The combined pumping unit for supplying* chambersif both the blower. and oil pump. However, in many cases the success of an oil feed system supplying a burner is directly dependent on the ability to maintain a tight oil feed system between the storage tank and the'burner and to exclude all air from the o il piping. This is important since, with a d1- rect pump feed to the oil burner, any small air bubble passing into the burner operates to momentarily extinguish the oil flame. Furthermore, the lubrication of the pump used 'as an air blower in such a system is best effected by injecting lubricating oil with the ingoing air on the suction Side of the blower unit and carrying the oil entirely through the blower and out with the outgoing air. Any arrangement which will permit the use of a small supply of oil without replenishment throughout a heating season for lubricating purposes is extremely desirable but of course if the fuel oil or other fluid which is handled by the one pumping unit is allowed to leak through into the blower unit along the drive shaft, a rapid dilution of blower lubricant will result, necessitating frequent refilling of the lubricating oil reservoir with a fresh supply of lubricating oil. By using a common end plate between the two pumping units and porting out the common drive shaft bearing into an oil sealing gland housed in said end plate, it is possible not only to exclude all air from the feed system of which the oil pump is a part but also to prevent any dilution of the oil for lubricating the blower unit with the lower grades of mineral oil normally supplied as fuel to an oil burner. Thus by means of the oil sealing gland the two pumps can be used respectively to supply oil directly from an underground storage tank to a domestic oil burner without admiXture with air and to supply substantially oil free air simultaneously to the burner under pressure suflicient to atomize the oil issuing from the tip of the burner.

The flow restricting device 128 positioned y between the oil pump an-d the feed line to the burner permits the use of a pump of convenient capacity operating at motor speed for delivering fluid only at the rate required by the burner, and at the same time, due to the rapidity with which the drive shaft 34 revolves, none of the pulsation set up by the intermittent bleeding of oil through the port 138 of the flow restricting device into recess 140 is felt at the burner tip. In the same way by employing a double acting blower unit and a relief valve such as 98 on the delivery line from the blower, it is possible to supply atomizing air in a continuous stream to the burner at a uniform controlled rate and under substantially uniform pressure.

It is to be understood that the present invention may be applied to other types of pump assemblies than those illustrated in the drawings. Likewise many modifications may be made in the invention without departing materially from its spirit and the present exempliiication is to be taken as illustrative and not limitative thereof.

The invention having been thus described, what is claimed as new is:

l. In a multiple fluid feed system, the combination with pumps arranged to deliver fluid separately from separate sources of supply to said system, of a drive shaft common to all of said pumps, a casting forming a common end plate for the working cylinders of each pair of pumps, and means to prevent the intermingling of fluid handled by one pump with fluid handled b any other pump.

2. In a dual fluid feed system, the combination with two pumps arranged to deliver two kinds of fluid separately from sources of supply to said system, of a drive shaft common to both of said pumps, a casting forming an end plate common to the working chambers of bothpumps, a bearing in said end plate journalling said common drive shaft, and means for preventing the intermingling of the fluid handled by one pump with the fluid handled by t-he other pump through leakage along the journalled portion of said drive shaft.

3. In a dual fluid feed system, the combination with two pumps arranged to deliver two kinds of fluid separately from sources of supply to said system, of a drive shaft common to both of said pumps, acasting forming an end plate common to the working chamber of both of said pumps, a bearing 1n said end plate journalling said common drive shaft, and means for preventing the intermingling of the fluid handled by one pump with the fluid handled by the other pump from leakage along the journalled portion of said drive shaft, said means comprising essentiall an overflow chamber, and passages porte out from the central portion of the bearing into said overflow chamber.

4. In a dual fluid feed system, the combination with two pumps arranged to deliver two kinds of fluid separately from sources of sup- Ely to said system, of a drive shaft common to oth of said pumps, a casting forming an end pla-te common to the working chamber of both of said pumps, a bearing in said end plate journalling said common drive shaft, and means for preventing the intermingling of the fluid handled by one pump with the fluid handled by the other pump including a sealing gland housed in said end plate and arranged to trap fluid leaking along the journaled portion of the shaft between the two pumps.

5. In a dual fluid feed system. the combination with two pumps arranged to deliver two kinds of fluid separately from sources of supply to said system, of a drive shaft common to both of said pumps, a casting forming an end elate common to the working chamber of oth of said pumps, a bearing in said end plate journalling said common drive shaft, means for )reventing the intermingli'ng ofthe fluid hand ed by one pump with the fiuid handled b v the other pump includino' a sealing `land housed in said end plate and arranged to trap fluid leaking along the journaled portion of the shaft between the two pumps, and, additional means to prevent fluid passing said trap, said means including an annular passage chamfered out of one end of said bearing, and means for maintaining substantially atmospheric pressure in said passage.

6. In a dual fluid feed system, the combination with two pumps arranged to deliver two J kinds of fluid separately from sources of supply to said system, of a drive shaft common to bot-h of said pumps, a casting forming an end plate common to the working chamber of both of said pumps, a bearing in said end plate journalling said common drive shaft, means for preventing the intermingling of the fluid handled by one pump with the fluid handled by the other pump including a sealing gland housed in said end plate and arranged to trap er having two working cylinders for supplyingsaid system, of a gas inlet port common to each of said blower working cylinders, a gas discharge port common to-each of said blower working cylinders, end plates common to adjoining cylinders, a drive shaft common to all of said cylinders, bearings journalling said drive shaft in each of said end plates, cams turned on the drive shafts in each of said cylinders, and annular pistons journalled on said cams and arranged to reciprocate in each of the cylinders as the shaft rotates, the cams operating the pistons in the two cylinders of the blower being set 180o apart on the shaft.

In testimony whereof I affix my signature.

BENJAMIN GREENFIELD.

fluid leaking along the journalled portion of i the shaft betweenthe two pumps, additional means to prevent fluid passing said trap, said means including an annular passage chamfered out of one end of said bearing, and means for maintaining substantially atmospheric pressure in said passage, said means comprising a central bore in the drive shaft opening at one end to the atmosphere and at the other end into a radial aperture ported out in said annular passage.

7. In a dual fluid feed system the combination with a pump having one working chamber and another pump having two working chambers for supplying two kinds of fluid separately from sources of supply to said system, of a drive shaft common to both pumps,

a casting arranged to function as an end plate common to the one chambered pump and one chamber of the two chambered pump, a bearing formed in said casting and arranged to journal said drive shaft, and passages porting out said bearing into a sealing gland arranged to trap fluid leaking along the journaled portion of the shaft between said pumps.

8. In a dual oil and air feeding system, the combination with an oil pump and an air blower arranged to supply oil and air separately from sources of supply to said system, of an end plate common to said pump and said blower, a bearing in said end plate, a rotatable shaft j ournalled in said bearing and common to said pump and blower, and means arranged to substantially prevent the leakage of pressure air along the journalled part of said shaft into said oil pump and to simuly taneously prevent the leakage of oil along the journaled part of said shaft into the blower.

9. In a combined gas and liquid feeding system, the combination with a liquid pump having one working cylinder and a gas blow- 

